1. Field of the Invention
The present invention relates to reciprocating-piston internal combustion engines having a crank drive and a transmission lever that is indirectly coupled with the piston and intersects the cylinder axis. The lever is articulated onto a connecting rod of a crank drive, on the one hand, and onto a bearing that is guided in the cylinder block but is adjustable, on the other hand.
2. The Prior Art
An internal combustion engine of this type is previously known from a schematic representation according to FIG. 3 in FR 607 215. A crank drive with connecting rod is coupled, by way of its outer connecting rod eye, with one end of a transmission lever that intersects the cylinder axis, and the other end of which is mounted on an excenter of a setting shaft disposed to pivot in the cylinder block. A second connecting rod, connected with the piston guided in the cylinder, is articulated on, approximately in the center region of the transmission lever.
By means of rotating the setting shaft, which is mounted in the cylinder block, with the excenter, displacement of the transmission lever crosswise to the cylinder axis takes place. Depending on the position of the transmission that has been set, a change in the position of the movement path of the piston in the cylinder occurs, and thereby a change in the compression ratio occurs.
When the transmission lever is displaced, the effective lever arm ratios of the two connecting rods that are articulated on do not change much with reference to the point of rotation of the transmission lever on the excenter of the setting shaft. The size of the stroke also does not change much.
Furthermore, an internal combustion engine in which a connecting rod moved by a crankshaft is guided by an axle, by way of its outer connecting rod eye, which axle is disposed at the end of a guide lever mounted to adjustably pivot in the cylinder block, is previously known according to FIG. 2 in DE 35 21 626 C2. This axle, which is guided both by the connecting rod and by the guide lever, engages into a guide, which extends in the longitudinal axis, of a transmission lever that can pivot, which is mounted in a fixed position on one end. This transmission lever pivots about a plane that runs approximately crosswise to the cylinder axis, whereby a second connecting rod connected with a piston is articulated onto its other end.
By means of adjusting the bearing of the guide lever in the housing, the axle connected with it and moved by the connecting rod on the crankshaft is also displaced. As a result, the effective lever length of the axle that also engages into the guide of the transmission lever changes.
The effective lever length of the second connecting rod, connected with the piston, on the transmission lever is constant. As a consequence, both the size of the piston stroke and the compression with the previously described drive mechanism in the case of an internal combustion engine can be varied by means of changing the effective lever length of the engaging axle.
It is a disadvantage that the setting range is low, and that as compared with the first embodiment of the invention according to FIGS. 1-3 discussed below, a guide lever additionally moves, with an oscillating movement, in addition to the piston, the transmission lever, and two connecting rods.